For as much as $32,000, plus travel to Peru, the Sarasota doctor advertises that he can treat devastating and incurable diseases including Parkinson's, Alzheimer's, ALS and Tay-Sachs, Aspen's fatal condition.

The kind of stem cell therapy he describes is not approved by the U.S. Food and Drug Administration. Without clinical trials and published research, it also is entirely unproven by American medical standards.

But few want to believe his promises more than the parents of children with Tay-Sachs, a rare genetic disorder that few survive beyond the age of 5.

"As parents, if somebody tells you there's no medicine, there's no treatment, there's absolutely nothing you can do, go home and plan her funeral, you'll take what you can get — if it sounds at all reasonable," said Brandy Brown, whose 22-month-old can neither walk nor talk, and suffers daily seizures. Aspen can no longer see and is losing her ability to move.

The Browns live in a small Alabama town that has rallied behind Aspen with raffles and motorcycle rides to raise money for Feinerman's treatments, which aren't covered by insurance. Now, with Aspen rapidly declining, the family has plane tickets to make a third trip to Peru next week.

Feinerman's critics accuse him of peddling hope to the hopeless, charging vast sums for treatments that are probably useless, and could even do harm.

But the 81-year-old pediatrician, who recently worked at a pain clinic in Tampa and also administers anti-aging treatments to adults, has no qualms about getting into the stem cell business. He insists he is practicing responsible medicine.

"I'm sure that Einstein was criticized. I'm sure that Thomas Edison was criticized," he said. "I must be getting to a point where people are at least listening."

• • •

Stem cells have the remarkable ability to divide rapidly, and to become all kinds of different cells.Scientists hope that their power could be harnessed to heal damage from aging, stroke, diabetes . . . you name it.

The International Society for Stem Cell Research, which Goldstein advises, says patients should be wary if they see claims based on patient testimonials, not research. Another red flag: Costly treatments that require patients to pay — clinical trials customarily do not charge participants, the group says.

Both apply to Feinerman's practice, StemCellRegenMed, but he says his methods are sound.

"We're not giving snake oil," he said. "We're doing what we feel has logic and science behind it."

• • •

Aspen Grace Brown was born at a healthy 7 pounds, 11 ounces, a beautiful, bright baby with chipmunk cheeks.

She hit her early developmental marks. But at 8 months, her motor skills seemed to be deteriorating. By her first birthday, she still wasn't crawling or talking.

One month later, she was diagnosed with Tay-Sachs. Doctors said she might live a few more years at the most.

"There are no words to describe the feeling that I had knowing that I was going to lose my first-born baby and very soon," Keith Brown wrote to his daughter in his online diary. "I had promised you the day you were born that I would protect you, but I couldn't stop this from hurting you. Totally helpless."

Tay-Sachs is best known for affecting Jews of Eastern European descent but can afflict people of many backgrounds. If two parents who carry the gene for Tay-Sachs have a child, the baby has a 25 percent chance of inheriting the disease.

The Browns grabbed onto a thin ray of hope when they heard about a boy from their community who had fallen into a swimming pool and suffered severe brain damage. His family was going to Peru for stem cell treatments from Feinerman, after which he improved somewhat, Keith Brown said.

The Browns called Feinerman. He told them he had never tried stem cell therapy on a child with Tay-Sachs. But he was willing to try.

"He has never given us false hope," Keith Brown said. "His exact words were, 'It's a shot in the dark.' "

• • •

In promotional photos, Feinerman wears a white coat and a Hawaiian lei. He retired to the island state after more than 40 years as a pediatrician in Miami. When he grew restless, he began to explore anti-aging medicine, which drew him to the nascent field of stem cell therapy.

In five years, Feinerman says, he has used stem cells to treat about 500 patients, from adults with ALS to brain damaged children. He says no one has gotten hurt.

Since treating Aspen, he says, his team in Peru also has treated five other Tay-Sachs children from Brazil and Germany. Those kids have all shown sustained improvement, he said, unlike Aspen who is now declining.

He said he has made submissions describing his Tay-Sachs work to two medical journals and does not yet know if his work will be accepted for publication.

He says he taught himself about stem cell therapy, but boasts about one formal credential, calling himself "Mayo Clinic trained" in newspaper advertisements and brochures. He did a one-year pediatric fellowship at the famed institution in 1956-57, according to his Florida medical license profile. He said he left to serve as a doctor in the U.S. Army in Germany.

His promotional materials do not mention the part-time job he took two years ago at a pain clinic on Busch Boulevard in Tampa. He says that it was only for six months, while he was building his new practice.

These days, his primary practice is Jouvence Medical in Sarasota, where he offers cell-repair treatments and hormone therapy to patients who want to look and feel younger.

But experimental stem cell therapy is his passion.

He sees nothing wrong with taking patients out of the country for unproven treatments. What patients pay barely covers his costs, says Feinerman, who is not licensed to practice in Peru. Instead, the actual treatment is done by his partner, Dr. Javier Paino, working with protocols developed with Feinerman.

Paino, who lives in Peru, went to medical school in South America, did some training in neurosurgery at Mount Sinai Medical Center in New York and received a Ph.D. in biochemistry from George Washington University.

Feinerman says he never guarantees treatment will work.

"I'm willing to accept the challenge rather than ignore the patient and say 'Well, there's nothing we can do.'

In October, three months after Aspen was diagnosed, the Browns flew to Florida to meet with Feinerman.

"We had heard the horror stories of these physicians preying on desperate families and basically just stealing their money," Keith Brown said.

They liked the energetic doctor who let them listen in on a conference call with a Tay-Sachs researcher, and patiently answered their questions.

"I just had a good feeling about him," Keith Brown said.

Back home, the Browns, whose income now comes from his job as co-owner of a construction company, took out a loan and held fundraisers.

Their first trip to Peru was in November. It took 20 minutes for Aspen to receive stem cells in a procedure similar to a spinal tap.

Within days, Aspen could hold up her head and follow people with her eyes, her father reported online.

The next day, the Browns received 700 e-mails and Facebook messages from people following her progress from as far as Belize, Brazil and Italy.

"You are the source of hope for a lot of desperate families," Keith Brown wrote in Aspen's diary.

After the second treatment in April, StemCellRegenMed issued a news release announcing the success of its "ground-breaking" treatment of Aspen and two other children with Tay-Sachs who had followed her path to Peru.

"It would be unethical and illegal to provide the experimental intervention in the U.S.," staffers were told to caution parents. "Also, when you are out of the country, there is no guarantee that the doctors do what they say they are doing."

The group's executive director, Sue Kahn, supports families in whatever decisions they make. But she wanted them to know that she had serious questions about Feinerman's company.

"The idea that something that could treat Alzheimer's could also treat Tay-Sachs, it doesn't make any sense, scientifically, to me," she said.

"These are diseases that people spend their lives studying. It's not a generic thing. It's just like thinking there's one drug that will cure all cancers. How is that possible?"

Ken Bihn wanted to learn more. In 2005, his daughter, Dakota, was diagnosed with a form of Tay-Sachs that appears later in childhood. The Cleveland family tried a controversial cord blood transplantation at Duke University.

Four years later, Dakota, who is nearly 12, continues to get worse. She can still see and give kisses, but no longer walks or talks and must use a feeding tube.

Her father, who talks to Keith Brown regularly, flew to Sarasota to meet Feinerman.

"I want to believe him," Bihn said. "No kid in the history of the world has survived Tay-Sachs, so if he says, 'I'll give you a 1 percent chance,' I'll take it. That's one percent more than I had."

Bihn said that when he asked for written information, Feinerman printed out medical material readily available online.

At Duke, doctors performed days of pre- and post-procedure tests on Dakota to measure any changes in her condition. Feinerman doesn't do that, Bihn noted.

Bihn said Feinerman told him that he takes stem cells from banked umbilical cord blood, using domestic sources. (Feinerman told the St. Petersburg Times he usually uses cells from a South American bank, but gets cells from U.S. sources for American children, including Aspen.)

In the laboratory, the stem cells are developed into neuron cells. Then Feinerman's team adds the gene that's missing in Tay-Sachs children, he said.

The combination of gene and stem cell therapy is delivered through the spinal channel, after which the cells are supposed to find their way to the child's brain and repair the damage, continuing to multiply.

Bihn didn't buy it.

"I want quantifiable evidence that these things are happening, not just observational evidence from a parent who wants to believe they did the right thing to help their child," said Bihn, who is president of the Cure Tay-Sachs Foundation. "I know too much now. I've been in this too long. I don't believe that Dr. Feinerman can help."

• • •

Until late April, Aspen appeared to be doing well. She was eating solid baby food again. Suddenly, she started having seizures, and her skin turned blue. She spent a week in the hospital.

Feinerman says Aspen's first treatment involved a protocol less advanced than what he has devised and used on his later Brazilian and German patients.

He's not going to charge for the round of treatment she will receive in Peru next week. But her parents still must pay for plane tickets, hotel and meals — on top of what they've already paid for experimental treatments.

Aspen's parents know the odds are long and the procedure risky. They've received calls from Tay-Sachs researchers warning them that the treatments won't work. But Feinerman is the only doctor offering her any chance at all.

"He's given us hope in a hopeless world," Keith Brown said. "And he is our only shot.''

Times researcher Shirl Kennedy contributed to this report. Letitia Stein can be reached at (813) 226-3322 or lstein@sptimes.com.

Q & AStem cells

What are stem cells?

Everyone has stem cells, which can reproduce themselves to repair tissues, and can mature into cells that perform a specific function, such as in the skin, muscle or blood.

Where do stem cells come from?

•Everyone has adult stem cells, which primarily function to maintain and repair the tissue in which they are found.

• Another source is umbilical cord blood, which some parents bank after childbirth.

• Most controversial are the embryonic stem cells typically from eggs fertilized in an in vitro fertilization clinic and then donated for research.

What is stem cell therapy?

A treatment that uses stem cells to replace or repair damaged cells or tissues in the patient, or drug therapies to get our own stem cells to work better. Although the concept is promising and a number of clinical trials are under way, it has been proven to work for only a few applications, notably bone marrow transplants for cancer patients.

For what diseases are stem cell therapies well established?

There are very few medical conditions for which there are proven stem cell treatments. Doctors have been transferring blood stem cells by bone marrow transplant for more than 50 years. Most other treatments are still experimental and have not yet been shown to be safe or effective.

Sources: National Institutes of Health, International Society for Stem Cell Research